The concept of studs for vehicle wheels that travel over mud and snow is old in the art. Typically, some type of spike or stud is located on the exterior of the wheel to grab or bite the ice or mud. With the innovation of snowmobiles and the advent of snowmobile racing on ice, there has been a need for a lightweight snowmobile stud for use on the elongated flexible snowmobile tracks. Since snowmobiles may travel in excess of 100 miles per hour, it creates a high centrifugal force on both the studs and the snowmobile track. Also, since the tracks are flexible and oftentimes only one-eighth of an inch thick, the studs must be lightweight, easy to apply and yet have sufficient tensile strength to bite the ice. One of the prior art snowmobile studs comprises a three-part stud having a back member which is threaded onto the rear end of the stud and a front member having a sharpened point which is threaded onto the opposite end of the stud to provide an ice stud. Other studs use specially designed bolts which have a large head for putting on the opposite side of the belt and a claw-like member which is attached to the opposite side of the track with a nut holding the claw onto the outside surface of the track.
Prior to the advent of studs for snowmobiles there existed studs in other arts, for example, the Ragon U.S. Pat. No. 2,426,974 shows a stud which fastens to an outer casing that attaches to an automobile tire.
The Russ U.S. Pat. No. 3,767,275 shows a traction element for a snowmobile racing track. The Russ device comprises a metal stiffener which extends across the track. Extending outward from the metal stiffener are a set of traction elements that bite into the ice.
The Husted U.S. Pat. No. 4,095,849 shows a protruding blade which engages the ice and snow. The blade is attached to the link chain of a power driven ski-type device.
The Swedish Patent No. 155,085 shows a bolt-like stud having two washer-like members that sandwich a tire casing from both sides.
Other embodiments of snowmobile studs are shown in the catalog sheet GRABBERS included herewith as part of the prior art.